In large bowl, beat marshmallow creme and butter with electric mixer on medium speed until blended. Beat in powdered sugar until fluffy. Divide frosting among 5 small bowls, about 1/3 cup each. Using the same 5 food colors, lightly tint frosting in each bowl to match cupcake colors.

Assemble each popper using 2 mini cupcakes. Cut tops off each cupcake horizontally (save bottoms for another use). Spread or pipe about 1 tablespoon frosting on cut side of 1 cupcake top. Form a sandwich by placing cut side of second cupcake top on frosting; press lightly. Repeat with remaining cupcake tops. Store loosely covered.